1. Field of the Invention
This invention concerns isotropic and anisotropic solutions of aromatic polyamide anions, the preparation of articles of manufacture from isotropic and anisotropic aromatic polyamide anion solutions and articles of manufacture made therefrom.
2. State of the Art
It is known that sodium hydride reacts with dimethylsulfoxide under anhydrous conditions with evolution of hydrogen to provide the so-called "dimsyl" anion. The dimsyl anion can be used to remove protons from a variety of compounds such as amines, amides, acetylenes and weakly acid hydrocarbons. Typical reactions have been described by Corey et al., J. Am. Chem. Soc., 87, 1345 to 1353, 1965, among others. Takayanagi et al. have extended the reaction of the dimsyl anion with amides to relatively low molecular weight aromatic polyamides and have used the aromatic polyamide anion thus formed to produce a variety of N-substituted products. See, for instance, J. Poly. Sci. (Polymer Chemistry Edition) 19, 1133 to 1145 (1981), which is hereby included by reference. However, this earlier work shows no recognition of solution anisotropy and there is nothing to suggest the preparation of useful articles such as films, fibers, coatings and coated substrates from dimethylsulfoxide or other liquid sulfoxide solutions of aromatic polyamides. Such solutions, both isotropic and anisotropic, over a wide range of concentrations, have now been found to be an excellent resource from which to prepare useful articles.
Other background publications include:
Takayanagi et al., Journal of Polymer Science, Polymer Chemistry Edition, Vol. 21, 31 to 39 (1983);
Ogata et al., Journal of Polymer Science, Polymer Chemistry Edition, Vol. 22, 865 to 867 (1984);
Takayanagi et al., Journal of Applied Polymer Science, Vol. 29, 141 to 151 (1984);
Takayanagi et al., J. Macromol. Sci.-Phys., B17(4), 591 to 615 (1980);
Takayanagi et al., Journal of Applied Polymer Science, Vol. 29, 2057 to 2067 (1984) and 2547 to 2559, and Vol. 27, 3903 to 3917 (1982 );
Bodaghi et al., Polymer Engineering and Science, 24, 242 to 251 (1984);
Takayanagi, Pure and Appl. Chem., 55, 819 to 832 (1983);
Moore and Mathias, in J. of Applied Polymer Science, 32, 6299 to 6315 (1986);
Takayanagi and Katayose, in J. Polym. Sci., Polym. Chem. Ed., 19, 1133 to 1145 (1981);
Japanese Patent Publications 58/7426, 59/223752 and 57/195136; U.S. Pat. No. 4,228,218; Yamada et al., J. Appl. Polym. Sci., 32, 5231 (1986); Flood et al., J. Appl. Polym. Sci., 27, 2965 (1982); and Aoki et al., Polymer Engineering and Science, 20, 221 (1980).
Aromatic polyamides are known to be soluble in sulfuric acid and hydrogen fluoride. However, the corrosivity of such solvents together with other factors attendant upon their use have combined to limit somewhat the development of commercial uses for the aromatic polyamides. With solvent systems such as amide-salt combinations, e.g., dimethylacetamide/lithium chloride, high salt levels are necessary to achieve concentrated polymer solutions. This, in turn, may affect utilization of these solutions for certain applications.